1) Field of the Invention
This invention relates to a pelleted animal feed composition and, more specifically, to a pelleted animal feed with increased hardness characteristics. Under the process of this invention, a nutritionally and pH balanced proportion of a water soluble form of calcium is added to an animal feed while the feed composition is in meal form, and which, when compressed, forms a pelleted animal feed with improved durability and less fines.
2) Background
At the present time, most animal feed manufacturers use some form of pelleting aid when producing their feed compositions. A major concern among animal feed manufacturers is the production of fines that occurs in the pellet mill, conveyers, coolers, sifters, bins, packers, etc. Recycling of fines is expensive since it greatly reduces production rates. In addition to concern about the expense, the repeated steaming and compression-temperature effects aggravate existing stability problems of vitamins and other additives. The importance of minimizing fines is therefore apparent.
One method of reducing fines in the production process is to decrease the pellet diameter of the pelleting die. However, this process requires a greater expenditure of energy, slows the production process, and causes more heat to be developed within the pellet which seriously affects the stability of certain labile ingredients within the feed formulation.
The other alternative is to incorporate a binding agent into the pellet composition. It is known in the prior art that binders and hardening agents can be utilized in the production of pelleted animal feeds to reduce the degree of fines. For example, present day manufacturing processes of pelleted animal feeds commonly use such binders as sodium or calcium bentonite (a tri-layered aluminum silicate, montmorillonite), collagen protein derivatives, cane or wood molasses, various starches obtained as the by-products from whole grain processing, natural gums and fatty acids, spray dried calcium lignosulfonates, cellulose gums, hemicellulose extract as the by-product in the production of pressed wood, lignin sulfonates comprising one or a combination of the ammonium, calcium, magnesium or sodium salts of the extract of spent sulfite liquor drained from the sulfite digestion of wood, abaca or sisal. These commonly used pellet binders and their methods of use are well known in the art. However, many of these pellet binders have serious disadvantages. For example, the use of many of the above binders such as lignin sulfonate or wood molasses are unpalatable to some animals and thus actually decrease the nutritional value of the animal feed to which they are added. This is of particular importance in feeds for monogastric animals such as swine, which require a feed with high nutritional value.
Another disadvantage of some of these binders is their incompatibility with certain drugs or antibiotics that may be present in the feed. For example, bentonite and certain other pellet binders are not permitted in combination with certain drugs in animal feeds because the bentonite has been shown to interfere with the analysis of the drugs by the accepted methods.
Other problems with these binders include widely fluctuating prices and/or quality, particularly when the binder is obtained as a by-product of another production process, for example cane or wood molasses.
From an economic standpoint, animal feed manufacturers would prefer to produce pelleted feeds at the lowest energy input. Adding binders to their feed compositions has proven to be an acceptable way of producing more durable pellets that are able to withstand the rough handling experienced during the manufacturing, packaging and transportation operations. However, the binders themselves add additional costs to the feed composition in the form of an additional ingredient that must be ordered, stocked, inventoried, and added as a separate step in the manufacturing process. It would therefore be a major advantage for an animal feed manufacturer to use as a binder a substance that has the ability to provide the necessary pellet hardening properties and also supply the necessary nutrients to the feed composition. That is, if the binder could also act as a source of important mineral requirements, substantial savings would result.
Under the process of this invention, it has been discovered that water soluble forms of calcium can be substituted for the normal, non-soluble sources of calcium traditionally used in animal feeds and also act as a superior pellet binder. The hardened pellets of this invention have less fines and thereby give better cost efficiencies by reducing the amount of recycling of feeds through the pellet mill and gives better consumer satisfaction though less waste. That is, the presence of fines within a packaged animal feed reduces feeding efficiency since they are typically inedible or undesirable to the consuming animals. In addition, there is a reduction in the destruction of nutrients that are susceptable to heat damage.
While it is known in the prior art that calcium oxide or calcium hydroxide can be reacted with water-soluble sugars to cause solidification of the resultant mixture into solid animal feed supplement blocks, these animal feed supplements require between 10 to 95 percent soluble sugar content.
These solid animal feed supplement blocks typically contain molasses as the source of soluble sugar in amounts ranging from 20 to 95 percent. The animal feeds of this invention contain at most 9 percent molasses, typically less than 6 percent, and in some instances contain no molasses at all. It was therefore unexpected that the desired hardness could be achieved in pellets containing little or no soluble sugar. That is, the improved pellet durability obtained by this invention was unexpected and not obvious since the reactive materials of the prior art are either not present at all or found in levels far outside those required by the prior art references, and thus would not be expected to contribute to the pellet hardness.